<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8" />
  <meta http-equiv="X-UA-Compatible" content="IE=edge" />
  <meta name="viewport" content="width=device-width, initial-scale=1.0" />
  <link rel="stylesheet" href="./css/index.css" />
  <title>记事本</title>
</head>

<body>

  <!-- 主体区域 -->
  <section id="app">
    <!-- 输入框 -->
    <header class="header">
      <h1>小黑记事本</h1>
      <input v-model="todoName" placeholder="请输入任务" class="new-todo" />
      <button v-on:click="add" class="add">添加任务</button>
    </header>
    <!-- 列表区域 -->
    <section class="main">
      <ul class="todo-list">
        <li class="todo" v-for="(item , index) in list" :key="item.id">
          <div class="view">
            <span class="index">{{index + 1}}</span> <label>{{item.name}}</label>
            <button class="destroy" @click="del(item.id)"></button>
          </div>
        </li>
      </ul>
    </section>
    <!-- 统计和清空 -->
    <footer class="footer" v-show="list.length > 0">
      <!-- 统计 -->
      <span class="todo-count">合 计:<strong> {{list.length}} </strong></span>
      <!-- 清空 -->
      <button @click="clear" class="clear-completed">
        清空任务
      </button>
    </footer>
  </section>

  <!-- 底部 -->
  <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
  <script>
    //添加功能
    //1.通过v-model绑定当前输入框
    //2.点击按钮,往上加
    const app = new Vue({
      el: '#app',
      data: {
          todoName:'',
          list:[
            {id:1 , name:'跑步一公里'},
            {id:2 , name:'跳绳200次'},
            {id:3 , name:'游泳100米'},
          ]
      },
      methods:{
        del(id){
          alert("删除");
          alert(id);
          this.list = this.list.filter(item => item.id !== id);
        },
        add(){
            if(this.todoName.trim() == '') {
              alert("请输入任务!!!");
            }else{
                this.list.unshift({
                  id:+new Date,
                  name:this.todoName
                })
            }
          this.todoName = ''
        },
        clear(){
          this.list == '' ;
        }
      }
    })

  </script>
</body>

</html>